


A Fun Route

by alex_awesome



Category: Undertale (Video Game)
Genre: "The Human" is the Reader, Blow Jobs, Breast Worship, Cunnilingus, Dubious Consent, Ecto-Penis, Ecto-Tongue, Explicit Sexual Content, F/F, F/M, Fingerfucking, Mating Cycles/In Heat, Nipple Play, No Plot/Plotless, Oral Sex, Plot What Plot/Porn Without Plot, Reader is female/has female parts, Reader is not Frisk or Chara, Reader-Insert, Robot Sex, Sans is big, Skeleton Heat, Sorta Dub-con, Vaginal Fingering, Vaginal Sex, Vibrators, Voyeurism, cum, magic cocks
Language: English
Status: Completed
Published: 2016-03-28
Updated: 2016-05-15
Packaged: 2018-05-29 18:03:49
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 5
Words: 5,509
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6386905
Author URL: https://archiveofourown.org/users/alex_awesome/pseuds/alex_awesome
Summary: <blockquote class="userstuff">
              <p>You are The Human. At first the monsters befriend The Human, but soon have other things to offer.</p><p>Why are all the monsters so eager to fool around with you? Who cares it's porn!</p>
            </blockquote>





	1. Prologue

**Author's Note:**

> This chapter is just setup, the smut will come with the next one.
> 
> (Y/N) is Your Name :)

The Human had finally convinced the monster woman, Toriel, to let her go. She would rather brave whatever was outside the Ruins rather than hide behind its doors. Toriel said it would be dangerous, and that The Human would meet friends and foes, buts mostly foes. With a warm embrace and a wish of good luck, The Human went through the doors, exiting the Ruins. 

A gust of cool air hit The Human’s face. She looked down and noticed the snow, and looked around and saw the dark looming forest. The chilly air was actually quite refreshing, and not too cold for The Human’s simple outfit of a cardigan and jeans, an thankfully sneakers and not sandals. She walked briskly forward, the snow crunching with each step. She hurried her pace, not wanting to meet any monsters that may happen to live in the surrounding woods. Though running seemed to be more of a problem than previously seen, as The Human’s foot caught on a thick root, sending her down into the snow and dirt.

She tried to stand, but upon looking back, she noticed that the green root that had tripped her was now wrapped around her ankle. She broke into a sweat when the surrounding snow began to shift and ungulate, more roots springing up, some of them looking like thorny vines. The Human used her other foot to kick at the root gripping her ankle. She spat insults at whatever monster was dragging her back.

“Go ahead, call for help…” A light voice said, though from where she did not know.

She panicked at this, thrashing and kicking as more vines curled around her legs, dragging her back still. She started to army crawl forward, trying to fight the unknown monster. A distant shadow started to move toward her, and she feared it was another unfriendly being. She decided to take her chances and call out to the figure for help, the struggle in her voice obvious. The figure stopped. It was hooded, and The Human couldn't see its face, but it was tall, at least a foot more than herself.

“Beat it.” The figure said, its voice deep.

The vines stopped pulling.

“Or?” The flighty voice came again. 

“You KNOW what. That’s no way to treat a newcomer, ya’ weed.” Came the deep husky voice.

Stillness set over the area as the two monsters seemed to think. Finally, the vines holding The Human slunk away, sinking back into the ground. The Human stood up, taking deep breaths as she dusted herself off. The savior monster walked over to her, finally able to be seen. It took off its hood, attached to simple jacket.

The Human almost yelped with surprise at the monsters face, or rather lack thereof. It was nothing but a six foot tall skeleton wearing clothing. It reached out its hand to the shivering girl. 

“Hey. I’m Sans. And I can see that you're a Human.” The monster said.

The Human reached out to shake his hand politely, and introduced herself.

“Well then (Y/N), I guess come to my place. You're all wet.” Sans laughed. 

The Human let Sans lead the way, his grip strangely tight.


	2. Sans

**Notes for the Chapter:**

> Ok, heres where the porn starts. Enjoy~

After a short journey through the light snowfall, The Human arrived at what appeared to be Sans’ house. Sans took her inside and promptly, though not exactly enthusiastically, showed her around. Of course, he mentioned his brother Papyrus, and how when he came home from his work at his post that he would want to capture The Human. Sans assured that this would not happen however.

“Your clothes are all muddy and wet, kid.” Sans said, rooting through a closet. “I’ll get ya somethin’ dry to put on and I’ll throw yours in the wash.”

The Human stood awkwardly as Sans continued to talk about himself and his brother, until he pulled out a large brown sweater. He threw it over to her and nodded toward another room.

“You can change in Pap’s room, I won’t tell him you were in there, heh.” He said with a shrug.

The Human looked down at the sweater. She guessed it would go to her knees, must belong to Sans’ brother. It was soft and unusually warm. Sans approached her, placing a hand on her shoulder.

“Go on, get changed. Don’t want you to catch a cold now.” He said, to which she obliged.

As much as The Human wanted to snoop around Papyrus’ room, she quickly yanked her cold, dirty clothes off of herself and replaced them with the warm sweater. The sweater was thick enough she felt safe taking off her bra, though she of course left her underwear on. It was fine as it was anyway.

There was a knock on the door. “You done in there (Y/N)? Or are you havin’ a look around?” Came Sans’ voice.

The Human quickly unlocked the door for him, showing that she had changed and not messed with anything in the room. Sans raised his brow, cracking a smile.

“Looks good on you. You're cute kid.” He said, the last of his words trailing into a whisper. The Human blushed. “Why don’t you go lay down on the couch, you’re in need of a rest.”

Sans walked her over to said couch where she got comfortable, and Sans covered her with a blanket. He trailed a hand over The Human’s blanketed hip, going further down her thigh. The Human froze.

“Try and get some rest, ‘k kid?” Sans chuckled, then turned off the lights before going back to his room.

~

The Human finally woke up. It was dark out, so she figured she must have been asleep for quite some time. She looked up toward Sans’ room, thinking if she should go tell him she was awake. His brother should be home soon. She sat up, but a voice from the dark caught her off guard.

“Lay back down, (Y/N). You're not fully rested.” It was Sans’ voice, deep and now a bit dark.

She whipped her head around and saw his silhouette standing at the front door. His body was shrouded in the dark, but his white smile and one blue flicker in his eye shone. 

“I just got off the phone with Papyrus. He’s out at a party with the Royal Guards, schmoozing up to them I’m sure.” He said. “Point is, we have the house to ourselves for a while…human.”

The Human broke into a sweat. Sans walked closer to her until he was at the foot of the couch. He climbed onto the couch and kneeled down at her feet. Reaching up, he pulled the blanket off of The Human, slowly letting it show more of her. He sighed.

“Forgot you had that thing on.” He said.

He reached up under the long sweater. His hands, strangely warm, brushed against her inner thigh, eliciting an involuntary moan. 

“You like that? I knew you were a little spitfire when I first saw ya, fightin’ and cursing at that flower bastard. You're not scarred, are ya.” Sans said softly into The Human’s ear, her hair standing straight up on her neck.

The Human asked why Sans was doing this.

“I have desires to yanno? Not many new, cute individuals find themselves in these parts.” He said, taking a hold of waistband of The Human’s underwear.

The Human choked back a yelp of both fear and excitement as Sans pulled her underwear down to her ankles. He chuckled deeply as he pulled them off fully, tossing them to the floor.

“Those are some cute panties, kid. They look better on the floor though.” Sans said.

Sans tugged The Human up by the collar before grabbing the sweater’s base. He lifted it swiftly over her torso and head, flinging it to the floor. The Human’s breasts bounced out after the clothing was pulled off and discarded. Sans’ smile grew when he took a look at the girl, fully exposed. 

“Oh man. You're quite something (Y/N).” He said, his eyes all over her body. 

He placed a hand on her breast. She moaned out as he brushed a thumb over her erected nipple. He laughed, and with his other hand he trailed down between her thighs. Her hands grabbed fistfuls of his jacket, and she buried her head into his shoulder as she felt a single bone finger trace her entrance.

“Holy hell, you're wet as rain.” Sans said deeply.

The Human started to breath heavily, with small moans here and there as Sans slid his finger into her agonizingly slow. He curled his digit once it was all the way inside. The Human bit her lip, trying to keep from begging. Begging for him to stop to save her from the embarrassment, or begging for more, she wasn't sure which. Sans added another finger to her soaking entrance.

“They go in and out so easily. You must be so excited, you little freak.” Sans said. “I must really be skelefun.” Sans laughed at this.

His other hand had been absentmindedly massaging The Human’s breast. He then leaned down so that his mouth was right above her nipple. He removed his hand and replaced it with a long, glowing blue tongue. He flicked its tip over the hard bud before wrapping his whole long tongue around her breast, saliva dribbling down her chest as it swirled around. The Human let out a small moan of his name.

“I knew you'd give in kid.” Sans said around The Human’s breast, his teeth grazing her nipple.

She grabbed his sharp hips when his fingers began to pump in and out faster, and his thumb had found her clit and began to rub in circles. The Human threw her head back in pleasure as Sans worked his fingers. 

He let her breast go. “I think my tongue is needed elsewhere.” He laughed and made a crude flicking gesture with his blue tongue.

He pulled his hands from The Human and put them on her thighs, spreading them. 

“Look at that pussy spread and drip for me. You really needed this.” Sans growled as he shoved he head between her legs.

The Human whined out as Sans twirled the tip of his tongue over her clit. He grazed it with his fangs and moaned into her folds. She put her hands on his head, resisting the urge to shove it into herself. He slowly slid the inches of his tongue inside her entrance, smiling as he tasted her.

The Human started to breath out curses laced with moans as Sans ate her out and fucked her with his tongue. He dug his fingertips into the flesh of her soft thighs, decorating them with raised red marks. Not too long into this, The Human started to feel her climax coming. Her hips bucked and her back arched. Sans noticed this, and immediately pulled his head away. 

“Not so fast, you'll cum when I want you to.” Sans growled. 

Sans sat up on his knees between The Human’s legs. He reached a hand down to his crotch, unzipping and unbuttoning his pants. The Human’s eyes widened as Sans reached into his boxers to pull out an inhuman cock. The member was bright blue like his tongue, and it had a glow to it. It wasn't the longest, but it was thick with a good girth, and had a perfect round head.

The Human whimpered as Sans stoked himself, gripping his cock and lining it up with her entrance. His tongue lolled out of his fanged mouth as he slid the head over her folds. She pleaded, pleaded for him to take her. Her legs spread to accompany his body, and he grabbed her hips.

He briskly pushed in, his length slipping in easily to the hilt. The Human moaned out the loudest time that night. Sans pulled back, only to shove himself back inside her. He started to get a rhythm going, pumping his glowing cock in and out of The Human, hitting her sweet spot directly, breathing heavily on her lower stomach as he leaned over her.

“Fuck (Y/N). Fuck that’s good.” Sans breathed, his voice still deep. “That’s it, take…take all of me.”

He felt The Human tighten around him, her orgasm approaching. His was close as well. His grip on her hips tightened, and she threw her head back.

“Heh, ready kid?” He stated more than asked.

The Human felt Sans push against her sweet spot again, and that did it. Her body convulsed and rocked with her orgasm, her eyes rolling back and drool seeping from her lips as she moaned. Sans thrusted a few more times before he let out a long whine with his own climax. He pulled out, his throbbing cock ready to unload. He aimed, and he came onto The Human’s stomach, his seed blue and glistening.

The two laid there for a while, catching their breath as their minds swam. At one point Sans got up and fetched a towel for The Human. She cleaned herself up, blushing bright red. They then sat there, trying to find words to say.

That’s when Papyrus walked through the door.

**Notes for the Chapter:**

> I take fic requests! The best place to ask is my Tumblr (see my profile)


	3. Papyrus

**Notes for the Chapter:**

> The other skelebro gets his x)

The Human shot up as soon as the door opened. She covered her nakedness with the towel Sans had given her, even though it was damp with his cum. At least poor Papyrus couldn't see her. Sans jumped to his feet. He had already tucked himself back into his shorts, but his face was still covered in blush and sweat, even more so now.

Papyrus let the door creak closed behind him as he stood and looked at the scene in front of him. He put a hand behind him and locked the front door, his eyes shifting side to side. Beads of sweat trickled down his bright orange face as he shuffled forward.

“Sans…is that…is that a human!?” Papyrus screeched. 

Sans’ face twisted. “Er, well. Yeh.” He admitted.

“How could you let a human into our home Sans!? And why is it not wearing anything!?” Papyrus questioned, his face and tone showing more worry than anger.

Sans put his hands out in front of himself. “Listen Pap, she was bein’ attacked by Flowey. I had to intervene. I brought her back here to let her clean up and all, and, well, one thing led to another…”

Papyrus put his hands to the sides of his head. “You had relations with the human? Are you crazy!? Even if you were... were in heat you should be able to control yourself!” He said shaking his head.

The room went silent. Awkwardness took over, and finally The Human spoke up. She said hello to Papyrus, told him her name, and informed him that she was no threat and that Sans had been good to her.

“(Y/N) ain’t nothing to worry about, Bro. She's scarred and alone here, we gotta help out.” Sans said. He smiled. “So throw her a bone, huh?”

Papyrus stomped his foot. “Puns? Now, Sans?” He noticed that The Human was holding back a smile. “Heh, guess (Y/N) liked it.”

“So whadda say?” Sans said. “Can she stay?”

“Well, she does seem harmless, but of course everything is harmless to The Great Papyrus.” He cracked a smile. “Well alright then, (Y/N), you may stay!”

~

Sans got The Human some new PJs, or rather a white shirt that came to the middle of her thighs. She still hadn't gotten her clothes back from the drier. After Papyrus had treated her and Sans to some food and asked plenty of questions about humans, he brought out blankets and pillows to the couch for her. The same couch which she and Sans fucked. It made her blush thinking about it.

It took awhile for The Human to fall asleep again, but finally she drifted off. Unfortunately she was woke by a hand shaking her. 

“Human, sorry to wake you!” Papyrus said in less than a whisper. He was sitting at The Human’s feet. “Do you need anything? I want you to be comfortable!” The clock informed The Human it was early morning, still dark.

She told him she was fine as she sat up and rubbed her eyes. Papyrus didn't say anything, and just started at her. She followed his gaze down to her clothed breasts. The white shirt she wore didn't cover her very well, as it clung to her breasts and allowed her erected nipples to poke through the fabric.

“(Y/N), why did you and Sans…uhm, have relations?” Papyrus asked softly.

The Human just told him that she got caught up in the moment, and that the idea of sleeping with a monster was exciting. Papyrus blushed. This must be the real reason he waked her, to ask questions.

“Did you…like it?” Papyrus asked, nervous and blushing orange.

The Human bit her lip and pulled a blanket over herself. She told him the truth: yes. She looked at Papyrus, and noticed that the front of his shorts were glowing orange. He saw that she noticed this, and quickly put his hands over himself.

“I’m sorry! It’s just that the thought of…having, uhm, s-sex..” He said that last word with trouble. “I find it, strange but exciting, the thought of having sex with a human. Oh I’m not being smart, I’m sorry. You see, I’m…in heat.”

The Human felt a wave of hotness wash over her, pooling at her groin. Papyrus seemed so innocent, but he also had urges of course. The Human put her hand on his knee. She wasn't sure if she was trying to comfort or further excite him. He let out a small whimper as The Human put her hand higher to his femur. She asked him what he meant by being in heat, to which he explained. He was horny, he wanted to mate, nature was telling him that. The Human put her hand even higher, nearing his pelvis.

“Please (Y/N). I was jealous, jealous of what Sans experienced with you.” Papyrus whimpered. 

The Human felt wetness between her legs. She told Papyrus that he to could have the experience.

Upon hearing this, Papyrus leaned over to her, pressing his teeth to her lips. A long orange tongue slipped out of his mouth and pressed into The Human’s. Their tongues danced as the front of Papyrus’ shorts became tighter, his glowing erection begging to be freed. With The Human’s approval, he unzipped. A good sized orange cock bounced out, hard, dripping, and glowing. The Human reached down for it, sliding its’ foreskin over the shaft, eliciting an excited moan from its’ owner. 

“(Y/N) please, I need, I need…” Papyrus whined, thrusting up into her hand. 

The Human threw the blankets off of her, crawling over to the skeleton. She bent down on her hands and knees and placed her lips to the head of Papyrus’ cock. He threw his head back and let out a moan.

“Oh OH (Y/N) yes!” He shrieked.

The Human wrapped her mouth around the head of his cock, lapping her tongue over its’ leaking slit. A toothy smile was smacked on Papyrus’ face, his orange tongue lolled out and drool dripping down his chin. The Human took more of his cock into her mouth, sucking it down until she got to the base. She began to bob her head, and Papyrus responded by bucking into her throat.

A noise sounded from the kitchen. Papyrus, in his ecstasy, didn't notice, but The Human did. She peered over the back of the couch, and almost stopped blowing Papyrus. Sans stood in the doorway. His eye sockets were half lidded, and his hand was stroking his exposed blue cock. He gave The Human a nod, as if to say “go on”. Getting off on his brother getting blown, it was sick, but it made The Human bob her head even faster, wanting to please Papyrus and give Sans a show at the same time.

“OOH (Y/N)! (Y/N)!” Papyrus shouted, he was close. 

The Human ran her hands over his femurs and pelvis, softy running her nails over the bone. Papyrus bucked hard a few more times. 

“I’m…going to, ohhh.” He gave a final thrust and orange cum exploded down The Human’s throat. Tastes of sugar invaded her mouth as Papyrus’ cum washed over her tongue. She swallowed it down eagerly. 

She looked over to where Sans was standing. He had quietly finished, his bone hand covered in blue seed, and his face flushed and sweating. The Human removed Papyrus’ now soft cock from her mouth. She looked back to the kitchen, and Sans was gone. 

Papyrus smiled and whispered a “thank you” before closing his eye sockets. The Human tried to shake him, but he was asleep, and the sun was just rising.


	4. Undyne

**Notes for the Chapter:**

> A bit short, but it's finals week. In a few days it'll be summer break and I'll have much more time to write~

The brothers knew they couldn't focus on things at hand with The Human around. They decided to take her to Waterfall to meet Undyne and stay with her for awhile. Papyrus had called her ahead of time and asked her to house The Human. Sans told him not to let her know what happened between The Human and them, but Papyrus had already slipped up. Undyne was silent at first, but then immediately said she wanted The Human to stay.

The brothers guided The Human to Waterfall and to Undyne’s house. They shook hands, albeit slightly awkwardly considering the relations they had shared, and told The Human to come by anytime. Sans winked as they left.

The Human took a deep breath and knocked on the door to the strange looking house. She stepped back as the door swung open, the “Undyne” the brothers had spoke of standing in the doorway. Her red hair swung in a large ponytail behind her and her pointed teeth glimmered as she smiled widely. 

“Hey punk!” Undyne cheerfully shouted. “Ya must be (Y/N)!” Undyne put a hand on The Human’s shoulder and led her inside. 

“Have a seat and I’ll get you some tea!” Undyne called. 

The Human sat at the kitchen table while she boiled some water. She looked over her body, admiring her scaly blue skin and muscles. Her ass was a perfect sphere, and she had small but perky breasts, and was braless. The Human blushed, embarrassed that she was already checking out her new friend.

“Here ya go! Perfect for this rainy weather.” Undyne said as she brought over two cups of steaming tea.

The two talked for what seemed like hours. Undyne bragged about her skills and duty as a royal guard a lot, but also asked The Human a lot of questions. Three cups in, things got more personal.

“So…Papyrus kinda let the secret out, (Y/N), said that you ‘did some naughty things’ with Sans and him?” Undyne blushed and chuckled as she spoke. 

The Human admitted to it. Silence filled the room. Undyne thew back the rest of her tea and stood up. 

“Anyway, enough chit chat, it’s late. You’ll sleep in my bed and I’ll take the couch.” She said.

The Human immediately offered to take the couch instead. Undyne slammed a fist on the table with a loud chuckle. 

“Don’t be dumb (Y/N)! You're my guest! Now get your ass to my room!” She grinned.

~

The Human did feel guilty for taking Undyne’s bed, but soon after crawling under the sheets and blankets she relaxed. She could not stop thinking about Undyne and how she knew about what she did with the skeleton brothers. The Human was embarrassed, but thinking back to the incidents she became flustered. She shut her eyes and begged sleep to take her from the confused thoughts, but it didn't come. She sighed. Sitting up, The Human stretched her arms over her head and cracked her neck. Looking to the bedroom door she noticed a dim light creeping under the crack. She got out of bed and cracked the door open, looking out and seeing Undyne sitting up on the couch watching TV.

The Human needed to talk to someone, anything to get away from the embarrassing thoughts. As she exited the bedroom Undyne turned to face her.

“Hey what are you doing outta bed, huh?” Undyne said. She was watching a horror movie. 

The Human said she couldn't sleep. Walking over to the couch The Human almost gasped. Undyne was in nothing but a bra and panties. Her defined abs and various scales and fins were on display, her near naked body illuminated by the television. Her red hair was let down and flowed over her shoulders and past her head’s shaved sides. The Human stared at Undyne and warmth shot to her groin.

“Undyne flashed her fangs and uncrossed her muscular legs. “Like what ya se kid?” She said.

The Human couldn't tell if she was serious or not. She furiously blushed and lied, saying that she was just taken by surprise by Undyne’s lack of clothing.

“I assume you don't mind it, on account of what you did with Sans and Papyrus.” She licked her fang. “So tell me, how hard was it for them to lure you in? Was it pressure or did you just…wanna have fun?”

The Human didn't want Undyne to think the brothers had pressured her into doing things she didn't want to do. She told her that she enjoyed it all.

“Would you do it again (Y/N)?” Undyne asked. She was blushing now, and tightly crossing her legs.

The Human wanted to, yes. She looked at Undyne’s half lidded eyes and sweating forehead, and her flushed cheeks and trembling frame. The Human knew she wanted it as well. The Human asked Undyne if she would fool around with another woman.

“Swing both ways, (Y/N). I actually gotta thing for Dr.Al…well you don't know her.” She said, trailing off.

The Human walked over to her, and knelt on the floor on her knees. Undyne bit her lip, a fang catching the skin. The Human put her hand on one of Undyne’s knees. 

“H-Hey punk, what are ya….do YOU swing that way?” Undyne stammered.

The Human confirmed, and started to push Undyne’s knees away from each other.

“(Y/N), you don't gotta get with me all like this…” Undyne was breathing heavily, her legs now fully spread.

The Human thought back to fooling around with Sans and Papyrus, and now looking at the beautiful strong Undyne before her, she knew she wouldn't have any regret. She put a fingertip to Undyne’s clothed sex, the thin panties not much at all a barrier. She stroked her finger down the covered slit, feeling the fabric dampen.

“If you wanna do this then quit your teasin’!” Undyne growled, but she still smiled.

In no time, Undyne’s panties were around her ankles, and The Human had full access to her smooth blue pussy. She circled her clit with her thumb, causing Undyne to throw back her head with a gasp. 

“F-Fuck..punk…” She moaned.

The Human inched her face closer between her legs, her mouth a hair’s width away from her sex. Slowly she spread her folds to expose her clit, and stuck out her tongue to bring to it. Undyne let out a low groan as The Human flicked her wet tongue over her hardened clit, and took it between her lips into her hot mouth to suckle. Undyne thrusted her hips rhythmically against The Human’s face, grinding and trying to get more stimulation.

“Oh God (Y/N), I need, I need it inside!” Undyne pleaded.

So The Human sped up her lapping, harshly stimulating Undyne with her tongue. She then brought two fingers to her entrance, and slowly began to push them in. Undyne was so wet it wasn't hard at all, the fingers sliding in with ease. The Human began to thrust them in and out, deep and hard. Undyne pushed herself down on them, crying out in pleasure as her clit was being lapped at alongside her pussy being thrust into. 

Undyne soon came, The Human’s lips and fingers becoming wet with her juices as she rode out her climax. After she calmed, she pulled up her panties and put a hand to her forehead, wiping away sweat.

“You deserve to get screwed real good (Y/N), and I know someone who can please you to no end, much better than me.” Undyne said. “So get some sleep, I’ll take you to him tomorrow.”


	5. Mettaton

**Notes for the Chapter:**

> The last chapter for this fic, I will be writing more reader insert and kink fics soon!

Undyne had taken The Human to the Riverperson, where they got a ride to Hotland. Undyne led the way inside the MTT Resort, a large and luxurious place. The Human followed Undyne as she led her through hallways, up an elevator, through more hallways, until the two walked back into a back room. Inside was a bedroom, and a…machine? 

A square machine on a single wheel was standing in front of a vanity mirror, applying makeup to its face-like screen. 

“Hey Mettaton, I brought a friend over! She's a human!” Undyne said, grabbing the machine’s attention. “This is Mettaton (Y/N), he's a robot built by the royal scientist.”

Mettaton turned around. “Ah! Hello darlings! Undyne, long time no see, and a human you say!?”

“There’s a favor I want to ask of you, MTT. I think you’ll like it pretty good to.” Undyne said.

She walked over to Mettaton and whispered something to him. He put his long arms to his screen, giggling. Undyne whispered to him for a while, The Human nervously waiting. Finally Mettaton rolled over to The Human. 

“(Y/N), it does seem like you deserve some real fun. Don't you worry darling, I’m going to treat you well.” Mettaton said.

Undyne smiled and walked to the door. “Don’t worry (Y/N), you'll have a great time! I’ll be down in the bar when you two are done.” She winked and closed the door behind her. 

Mettaton rolled over to the door and locked it before dimming the lights. “If you think this form is attractive, you just wait!” He said.

He reached behind himself, seeming to have pressed a button. Suddenly his square body began to move and change. Steam was expelled through his sides and his metal body shifted in order to create his new form. A cloud of smoke and steam erupted as Mettaton stepped out in his new form. He posed and flaunted his miraculous and sexy body.

“So are you ready to have your world rocked (Y/N)?” He asked The Human.

The two made their way to the large bed in the room, where Mettaton laid down and positioned The Human on top of him. His long metal arms extended and started pulling The Human’s clothing off. Soon she was naked, and Mettaton’s arms wrapped around her body, feeling her body’s curves, and squeezing her breasts and stomach and thighs. The Human moaned and heat shot to her groin. Mettatton pushed a finger into The Human’s sex, making a “come here” motion.

“Do you want more (Y/N)? I know just what you want.” Mettaton said in a sultry voice.

With his extended arms, Mettaton picked The Human up and moved her to hover over his crotch. A soft metallic scraping noise started up, and a thick metal cock rose from between Mettaton’s thighs. A faint pink glow emitted from his cock, and a pink goo dripped from the head.

Mettaton lowered The Human onto his cock, the pink precum and her own wetness providing enough lubrication for it to slide into her. His cock was warm and thick, and it stretched her as he hilted himself. Mettatton’s cock base brushed against The Human’s hard clit, and she ground herself onto him, trying to fill herself more.

“Oh just wait until you see my special function.” Mettaton chuckled. 

With that said, Mettaton’s cock started to buzz as it began vibrating. The Human let out a loud scream-like moan as she felt the thick vibrating cock buzzing away deep inside her and against her throbbing clit. Mettaton lifted The Human up to where he was almost emptied of his cock, then he shoved her back down, filling her roughly again. She began to bounce on him herself as Mettaton put his hands to her breasts to squeeze and thumb over her nipples. The Human let out a series of “Yes!”s and “Harder!”s until finally Mettaton thrust up hard into her.

The Human came, her body shaking uncontrollably as she climaxed. Mettaton orgasmed with her, releasing his pink cum into her with an “Ohhhhhh yes!”. The Human hopped off of his cock, which started to retract back into his body. They panted and smiled in their post climax haze.

“Aren’t you glad Undyne brought you to me darling?” Mettaton said.

The Human was so glad she had fallen into the Underground. Who knew monsters were so nice.

~

The End

**Notes for the Chapter:**

> my tumblr is mara-awesome, feel free to chat me up!


End file.
